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Radeon vs. RadeonHD Drivers In H1'08

03-19-2008, 07:40 AM

Phoronix: Radeon vs. RadeonHD Drivers In H1'08

For Linux distribution vendors, right now is proving to be an awkward time for them as they decide which ATI driver will ship as the default choice in their spring distribution refresh. The problem used to be whether to ship a binary-only driver in the distribution in order to provide "out of the box" support for all available graphics hardware, but on the ATI/AMD side the software distributors are now facing the challenge of which open-source driver they should call the de facto standard. In this article we are briefly looking at the matter of the xf86-video-ati vs. xf86-video-radeonhd drivers, the highly political issue of AtomBIOS, and what some of the popular Linux distributions are deciding to use this spring.

On the NVIDIA side, distribution vendors may soon find themselves in a similar boat choosing between the official xf86-video-ati 2D driver and the reverse-engineered Nouveau driver, which will be capable of both open-source 2D and 3D support.

That should be the nv driver?

Still a nice article. Thank you. I enjoy following Radeon development with Phoronix articles.

Comment

For Linux distribution vendors, right now is proving to be an awkward time for them as they decide which ATI driver will ship as the default choice in their spring distribution refresh. The problem used to be whether to ship a binary-only driver in the distribution in order to provide "out of the box" support for all available graphics hardware, but on the ATI/AMD side the software distributors are now facing the challenge of which open-source driver they should call the de facto standard. In this article we are briefly looking at the matter of the xf86-video-ati vs. xf86-video-radeonhd drivers, the highly political issue of AtomBIOS, and what some of the popular Linux distributions are deciding to use this spring.

Right now I'm using the RadeonHD driver from their GIT repository on my home machine, but I'm not sure I'm happy with it so far. This is a Hardy Heron box too, so I'm sure I'm just running into all the usual teething problems with Beta software.

I'm very willing to try both, and I'm actually looking to see if I can enable Compiz stuff on my X1600 Silent card.

The only complaint I have right now is that I think my old Matrox G450 had crisper text, and with my bad eyes, that's a big issue. Not sure yet, and I haven't had time to play. It could just be my font choices right now.

I'd love to see an article which tests both drivers on an R500 GPU to see how the performance and features compare.

Comment

If you keep adding support to new cards in the same driver (radeon), it's going to make the driver slower even for the old cards due to the penalty of card-specific if statements. So it would be better from a performance p.o.v. to have a new driver like radeonhd. What's even more sad is that once someone indroduces support for r500/r600 into the radeon driver, no one will take the time to remove that support if it becomes superfluous, and were stuck with two drivers forever and a split tester base.

Also, AtomBIOS sounds like just an excuse for AMD to not provide documentation. Furthermore, if you have a bug in AtomBIOS, you can't fix it unless you re-flash the card which would be dangerous.

Comment

Also, AtomBIOS sounds like just an excuse for AMD to not provide documentation. Furthermore, if you have a bug in AtomBIOS, you can't fix it unless you re-flash the card which would be dangerous.

It's the same problem as with the bad bioses on some old laptops with an i810 (you cannot use the display native resolution using the straight bios of the card). Really not a good situation to be in, so relying on the bios is a bad thing.

Comment

If you keep adding support to new cards in the same driver (radeon), it's going to make the driver slower even for the old cards due to the penalty of card-specific if statements. So it would be better from a performance p.o.v. to have a new driver like radeonhd.

Here's the issue -- only the modesetting hardware changed between 4xx and 5xx. The acceleration hardware is largely unchanged, so the same code generally runs on both 3xx/4xx and 5xx parts.

Also, AtomBIOS sounds like just an excuse for AMD to not provide documentation.

Sure, but we already provided the documentation

We are providing complete documentation for what the registers do, and in some cases are creating new docs which explain how the pieces fit together. What we were hoping not to have to provide is the "set this register to 0x7... set that register to 0x0015fe2" level of detail since that was already coded and heavily tested in AtomBIOS.

Furthermore, if you have a bug in AtomBIOS, you can't fix it unless you re-flash the card which would be dangerous.

One of the design criteria for AtomBIOS was the ability for the driver to over-ride any table with a newer version if required. We have been using AtomBIOS for the Windows drivers for a few years now and have never had to patch a table, but the mechanism is there.

It's the same problem as with the bad bioses on some old laptops with an i810 (you cannot use the display native resolution using the straight bios of the card). Really not a good situation to be in, so relying on the bios is a bad thing.

Actually, that's not the case with AtomBIOS. We don't restrict you to specific modes. There is a traditional VBE / BIOS layer running on top of AtomBIOS which does have a fixed mode table, but that only affects VBE calls.

Comment

The ati/radeon devs are doing a great job, but in my opinion, RadeonHD is the way to go if you have R500+ hardware... at this early state I found RadeonHD to be rockstable already while ati/radeon has serious problems with TexturedVideo and 2D acceleration for me, and I think the RadeonHD driver will take the lead in performance and stability later this year...

Great article, and I have to say that Mandriva is doing the best in my opinion by using ati/radeon for R100-R400 (and Mandriva keeps their packages uptodate) and RadeonHD for R500+. I never liked Ubuntu and I don't think it is easy for the normal user if he has to compile his drivers by himself, because Ubuntu is already outdated before a new release arrives, and Ubuntu doesn't update their packages at all... Mandriva is overall very underrated and Ubuntu overrated...